Cathode forming machine



Nov. 9, 1943. J. GLANS CATHODE FORMING MACHINE Filed Dec. 14, 1940 5Sheets-Sheet l lNVENTOR ATTORNEY Nov.9, 1943. 9 L NS- 2,333,997

CATHODE FORMING MACHINE Filed Dec. 14, 1940 3'Sheets-S heet 2 I 3 I QINVENTQR a! 19 1 3e ATTORNEY NOV. 9, 1943. J GLANS CATHODE FORMINGMACHINE Filed Dec. 14, 1940 3 Sheets-Sheet 3 INVE mapk G 8% g ATTORNEYPatented Nov. 9, 1943 CATHODE FORMING MACHINE Joseph Glans, Bloomfield,N. J., assignor to Radio Corporation of America, a corporation ofDelaware Application December 14, 1940, Serial No. 370,157

7 Claims.

My invention relates to sleeve or tube manufacture, particularly to lockseamed cathode sleeves with integral tabs.

In making wrapped and seamed sleeves or tubes in very small sizessuitable for use as cathodes in radio tubes, the problem becomesdifflcult of making uniform and strong seams along the side of thesleeve. Often the blank, from which the sleeve is made, shifts slightlywith respect to the mandrel around which the blank is wrapped, andflanges of the proper width cannot be creased along the blank edges formaking the seam, and defective sleeves result. Where laminated tabs,integral with the end of the sleeve, are formed by extending the edgedportions of the blank beyond the end of the blank, as suggested byHaslauer 2,029,482 of February 4, 1936, it is particularly importantthat the sheet metal be held from shifting during wrapping and seamforming operations. .Further, tools and dies for wrapping the blankaround the mandrel must prevent slack in the blank on the mandrel toinsure uniform and accurate sizing of the flnished sleeve.

An object of my invention is an improved machine for making wrapped orseamed sleeves or tubes with means for making strong and uniform sleevesthat are accurately sized.

A further object of my invention is an improved machine for making lockseamed cathode sleeves with one of the longitudinal edge portionsextended beyond the end of the sleeve to provide a rigid integral tabfor thesleeve.

The characteristic features of my invention are defined in the appendedclaims and the preferred embodiment of the machine is described in thefollowing specification and shown in the accompanying drawings in which:

Figure 1 is a schematic perspective view of my machine showing thepositional relationship of the essential parts of the machine;

Figure 2 shows one completed sleeve with a one-layer integral tab madeon my improved machine;

Figure 3 shows a second sleeve with a twolayer integral tab made on mymachine;

Figure 4 shows a portion of ribbon metal stock from which the sleeve ismade, with a rectangular hole stamped in the ribbon preparatory toseverance of the blank from the ribbon for the .wrapping and seamingoperations;

Figures 5 to 11 show in end view the mandrel and dies during thewrapping and seam forming operations;

Figure 12 is an enlarged and detailed perspecaccurately center the stripover the anvil.

tive view of mechanism for actuating in a horizontal and verticaldirection two of the seam making dies; and

Figure 13 is an enlarged detailed peispective view of strip feedingmechanism for my novel machine.

One sleeve made with my improved machine, shown in Figure 2, comprises athin walled cylinder l of any desired cross sectional shape closed by aconventional four-layer lock seam. The edge portions or flanges 2 and 4along one side of the sheet metal blank from which the cylinder is made,interlock with flanges 3 and 5 along the other edge of the blank. One ofthe layers of the seam, 3 as shown in Figure 2, extends beyond the endof the seam and may be used as a support or electrical connector for thesleeve. Alternatively, a double thickness tab, as shown in Figure 3, maybe conveniently made by extending flanges 2 and 4 beyond the end of thesleeve, the two laminations of the tab being integrally joined alongtheir edges throughout their length. For convenience of description, thereference characters applied to the flanges in Figures 2 and 3 areapplied throughout the other figures of the drawings, to thecorresponding edge portions of the ribbon and blank from which thecylinder is made.

In Figure 1 the strip metal or ribbon from which the sleeves are made isfed from the left and is moved forward step-by-step by stepping jaws 6which grip the strip and for each step advance the ribbon a distanceequal to the combined length of the finished sleeve and its integraltab. The two jaws close upon the ribbon and move forward while thegripping block 1 is elevated. The jaws release their grip upon theribbon and return as the gripping block holds the ribbon against thestationary anvil 8 to prevent backward movement of the ribbon. Theribbon passes under the guide block 9 with one edge extending beyond thealigned sides of the anvil and guide block, and between each feedingstep this extended edge is folded down by the flanging plunger I 0. Theflange, designated by 4. thus formed along the edge of the ribbonstiffens the ribbon so that it may be pushed without buckling. Thestepping jaws 6, more fully hereinafter described in connection withFigure 13. are curved to groove the ribbon and further stiffen theribbon. This flange 4, further, may be held against the side of theanvil to guide and The blanking die ll reciprocates above a rectangularopening in the anvil and for each downward movement of the blanking diecuts a rectangular window in the strip, leaving that portion of theribbon ahead of the blanking die attached to the oncoming ribbon only bythe edge portions 2 and 4 on one side and 3 on the other side of theribbon. It has been found convenient to press a transverse groove in thestrip with beading die L2, while the window is being cut, when a.circumferentially embossed bead la, Figure 3, is desired around the tabend of the sleeve. The beading die may be placed where desired to formthe head at any point along the blank.

The next step forward of the ribbon carries the edge portions of theribbon opposite the window beneath cut-off knives I3, i4 and I5. Two ofthe knives l3 and i4 may be mounted on a single block detachably securedto one end of the cross head l6 while the third knife is detachablymounted on the other end of the cross head. The cross head and knivesare guided along the side of the stationary anchor block I! spaced abovethe anvil 8. The cutting edges of the knives reciprocate over the edgeportions of the ribbon opposite the corners of the window, and byinterchanging the knives, an integral tab may be left on either side ofthe blank. The double knife block is shown, in Figure l, on the near endof the cross head and in position to cut the entire flanged edge of theribbon opposite the window, while the third knife i in position to outonly the trailing end of the opposite strip edge. A blank thus cut willappear, when finished as a cylinder. with the single layer integral tabof Figure 2. If the block carrying knives l3 and I4 are interchangedwith knife i5, the finished cylinder will have an integral two-layer tabas shown in Figure 3.

When moved into the tab cutting position, the blank is carried under themandrel I 8 about which the blank is wrapped and, accordingto one of thecharacteristic features of my invention, the blank is firmly pressedagainst the underside of the mandrel by the foldin die I9 before theknives descend to sever the blank from the ribbon. At no time is thesheet metal blank left free to shift laterally under the mandrel.

To prevent upward bending or deflection of the rather long thin mandrelby the folding die, the mandrel is supported from above by the backingdie 20 which descends to the mandrel as the folding die moves up frombeneath to press the blank against the mandrel. After the blank issevered from the ribbon, the folding die continues its upward movementto fold the blank around the mandrel and push the two sides of the blankinto the upstanding parallel positions shown in Figure 5. Wrapping iscompleted and the lock seam is made with the stretching dies 2i and 22and the hanging dies 23 and 24, as more fully hereinafter described andshown in Figures 5 to 11.

The mandrel I8, supported at opposite ends of the blank by anchor i1 andstripper block 25, is withdrawn from the finished sleeve as best shownin Figur 1 by longitudinal movement to the right through the strippingblock. If the sleeve thus stripped from the mandrel does not fall freeof the dies, it may be delivered to a suitable receptacle by a blast ofair. Preferably the stripping block is positioned close to the end ofthe dies so that the two points of support for the mandrel may be nofarther apart than the combined length of the sleeve and its tab.

Drive means for the various parts of my improved machin are interlinkedwith a common mechanical connection between each moving part and itscam. My machine may, because of the simplified movement of parts, beoperated at a speed of over complete sleeve making operations perminute. Sleeves of different lengths may be made by simply adjusting thelength of travel of the stepping jaws and different diameters or crosssectional shapes of sleeves may be made by inserting the appropriatemandrel.

The positional relationship of the horizontally and vertically movableseam forming dies are shown in end views in Figures 5 to 11. The blanklying on the upper flat surface of the folding die I9 is firmly heldagainst the undersid of the mandrel as the cutting knives sever the tabsections from the ribbon, and after the backing die 20 moves down intocontact with the upper ward to fold the blank into the U-shape shown inFigure 5. throughout the remaining seam forming operations. Preferablythe recess in the folding die in registry with the mandrel is fitted, orshaped to conform to the mandrel, and is of such a depth that the'flattop surface or end of the folding die comes to rest opposite the centerline of the mandrel. The backing die is then raised as the stretchingdies 2| and 22 move in from either side. The forming surfaces of thestretching dies conform to .the shape of the upper quarter sectionsofthe mandrel and completely enclose the cylinder from the top of thefolding die to the flanges 4 and 5 at the top of the cylinder. Thestretching dies move in and firmly press the cylinder to the mandrelthroughout its circumference. With the forming surfaces of thestretching dies entirely above the center of the mandrel the inwardforce of the stretching dies delivers to the upper half of the cylindera stretching movement toward the flanges at the top. The stretching diesremain in the position shown in Figure 6 and hold the cylinder wallsunder tension while the flanges are folded and interlocked. Flangingdies 23 and 24 move in from either side of the upstanding flanges 3, 4and 5 as shown in Figure 7 and fold flange 3 over the end of flange 4and the left die is withdrawn as the backing die moves down to fold theflange 3 over the outer edge of flange 4, as shown in Figure 8.Thereupon the back ing die is retracted and the left fianging die againmoves in to complete the interlock between flanges 3, 4 and 5. Theupstanding lock seam is now ready to be laid over and flattened againstthe wall of the cylinder. As shown in Figure 10, left hand flanging diemoves back, right hand flanging die moves forward a short distance tolay over or incline the lock seam. Now both the stretching dies andflanging die move back, forming die 26 moves to the left displacing thebacking die 20, and then moves downward to press the seam into thelongitudinal recess in the top of the mandrel.

It has been found expedient to mount the backing die 20 and the formingdie 26 in side-by-side Here the folding die remains side of the mandrelthe folding die proceeds uptween laterally extending ears on the upperends of the dies. The ears 33 are sufficiently long to permit thetransverse movement of the dies from the position shown in Figure to theposition shown in Figure 11.

The stepping jaws 6 shown in greater detail in Figure 13 reciprocatelengthwise of the ribbon and are guided in the V-way of the stationaryblock 611, power for the reciprocatory movement of the blocks beingsupplied by cam 6b. The two blocks are pressed together by the pivotedcam lever Go to positively grip the ribbon during the forward movementof the jaws and are moved apart to slightly relieve the pressure on thestrip upon the return travel of the jaws. According to one feature of myinvention the clamping surfaces of the jaws 6 are slightly curved sothat the ribbon is grooved lengthwise by the jaws as the jaws slide tothe left over the ribbon. That portion of the ribbon to the right of thejaws is strengthened by the concaved cross sectional configuration andcan be pushed through the dies and guides of the machine withoutbuckling or bowing. My improved ribbon feeding mechanism is positive inoperation, accurately feeds the ribbon to the dies, and stiflens eventhe most foil-like strip material so that it can be easily handled in mysleeve making machine.

My improved lock seamed cathode making machine is simple inconstruction, easy to adjust and fast in operation. It accurately formsand sizes sleeves from thin metal stock.

I claim:

1. A machine for making lock seamed cathode sleeves comprising a metalstrip feeding mechanism for feeding the strip lengthwise step-by step,means for bending a right angle flange along the edge of the strip, amandrel axially aligned with the strip, a .folding die beneath saidmandrel, said folding die comprising a block of metal flat on its upperside and having a longitudinal groove in registry with the mandrel, saidgroove being in depth equal to approximately one-half the verticaldiameter of said mandrel, the mandrel and folding die being positionedat the end of said strip to receive one section at a time and to gripand fold each section in succession, cut-ofl knives for severing eachsection from the end of said ribbon, stretching dies reciprocable alongsaid upper surface of the folding die to wrap said section around themandrel, fianging dies reciprocable on said stretching dies, a backingdie above said mandrel reciprocable in a direction normal to thedirection of travel of the fianging dies, the movements of said flangingdies and said backing die being coordinated to interlock said flange andopposite edge portion of the section, and a forming die to press theinterlocked edges against said mandrel.

2. A machine for making locked seam cathode sleeves comprising arectilinear horizontal mandrel, a folding die reciprocably mountedbeneath said mandrel and having in registry with the mandrel a shapingsurface fitted to the lower half of said mandrel, a metal strip feedingmechanism for feeding a sheet metal strip lengthwise step by step toplace the end portions of said strip between said'mandrel and saidfolding die, cutoil knives for cutting off th portion of strip betweensaid folding die and said mandrel, actuating means for moving saidfolding die upward to grip theend portion of said strip between saidfolding die and said mandrel, actuating said cutoff knives to sever theportion gripped by said folding die, and continuing the upward movementof said folding die to fold the severed portion of said strip around themandrel, means for bringingtogether and joining the edge portions of thefolded blank by an upstanding seam formed from said portions, avertically reciprocable backing die above said mandrel to support saidmandrel against the thrust of said folding die, a forming diereciprocably mounted above said mandrel side by side with said backingdie to press the seam and the sleeve down against the mandrel, and meansfor transversely shifting said backing die and said forming die insuccession into operative position above said mandrel.

3. A look seamed cathode making machine comprising a mandrel, two spacedsupports for said mandrel through which said mandrel may longitudinallyreciprocate, a vertically reciprocable folding die beneath said mandrelbetween said supports shaped to conform to the lower half section of themandrel, a horizontal reciprocable stretching die on each side of saidmandrel with forming surfaces shaped to conform to the upper quartersections of the mandrel, means to interlock opposite edge portions of ablank wrapped around said mandrel, and means to press said interlockedportions against said mandrel.

4. A machine for making lock seamed cathode sleeves comprising amandrel, a vertically reciprocable folding die beneath said mandrel,means for feeding a sheet metal blank lengthwise between the mandrel andfolding die, horizontally reciprocable stretching dies on either side ofthe mandrel for pressing said blank into snug engagement with themandrel, horizontally reciprocable flanging dies on either side of themandrel for holding upstanding longitudinal edge portions of said blankwrapped around said mandrel, a backing die, a forming die, said backingand forming dies being reciprocably mounted side-by-side above saidmandrel, means for transversely shifting said backing and forming diesto operative positions above said mandrel, and drive means forsuccessively moving the folding die, the stretching dies, the flangingdies and the backing die toward the mandrel to wrap and form a seam onthe blank, and for moving the forming die to flatten the seam againstthe mandrel.

5. A machine for making seamed sleeves com prising a mandrel, avertically reciprocable folding die for folding a sheet metal blankupward around the bottom of the mandrel, means for bringing'together andjoining the edge portions of the blank, a backing die vertically movableagainst the top side of the mandrel to support the mandrel, a formingdie vertically movable against the top side of the mandrel for pressingthe interlocked edge portions against the mandrel, said backing die andforming die mounted side by side above said mandrel, and means forshifting the two last mentioned dies laterally above the mandrel.

6. A machine for making seamed sleeves comprising a horizontal mandrel,a folding die reciprocably mounted below said mandrel to fold a. sheetmetal blank upward and around the bottom of the mandrel, a backing diereciprocably mounted above the mandrel for supporting the mandrelagainst the thrust of said folding die, means for bringing together theedge portions of the folded blank and joining said edge portions by anupstanding seam formed from said edge portions. a forming diereciprocably mounted side by side with said backing die for pressing theseam and the sleeve down against the mandrel, and means for laterallyshifting said backing and forming dies to bring said dies successivelyinto operative position above said mandrel.

'7. A machine for making seamed cathode sleeves comprising a mandrelhaving the cross sectional size and shape of the sleeve, a folding dievertically reciprocable to and from said mandrel, said die having agroove in registry with and formed to fit the lower portion of themandrel and adapted to bend a sheet metal blank into a U- shape fold onthe mandrel, means to push the two legs of the folded blank into snugcontact with the upper portion of th mandrel, said means comprising twostretching dies horizontally reciprocable to and from opposite sides ofthe mandrel, the forming surfaces of the stretching dies being shaped tocover the portions of the mandrel not covered by the groove of saidfolding die, and means for joining'the longitudinal edges of the legs ofthe folded blank by a seam formed from the blank while the blank ispositively held on v the mandrel by the folding and stretching dies anda forming die reciprocably mounted above said mandrel side by side withsaid folding die for pressing the seam against the mandrel, and meansfor transversely shifting said backing and forming dies to operativepositions above said mandrel.

JOSEPH GLANS.

